This invention relates generally to spools which have conical ends and are adapted to carry appreciable, heavy quantities of wire; more particularly it relates to low-cost spools of the type that can be readily assembled for use and thereafter disassembled if desired, to facilitate their shipping and storage.
In the past a number of different spool constructions for holding large, heavy quantities of wire have been proposed and produced. Most prior spools consisted of a number of sheet-metal sections which were assembled to one another by welding. Generally, the cost of producing such spools was excessive, due to the relatively heavy gauge metal which was required, in addition to the cost of labor involved with the various welding procedures.
Various spool constructions of the take-apart variety have also been developed over the years. U.S. Pat. No. 2,295,222 discloses one such spool, having a central body portion and single conical end flange releasably secured thereto. The bore of the body portion is threaded, and a corresponding threaded portion on the end flange is received therein. While this construction was considered satisfactory under certain circumstances, it can be appreciated that the costs involved with providing mating thread formations on multiple sheet-metal parts tended to be rather high, resulting in a product which was prohibitively expensive for many applications or installations.
Another prior spool construction is illustrated in U.S. Pat. No. 1,786,366. The device disclosed therein involves a pair of disk-like end flanges which are fitted to a central spool body that is constituted as an iron pipe. Annular bead formations on one side of each flange are employed for keying the flanges to the body. Multiple bolts are utilized, located off-center with respect to the axis of the spool for securing the flanges together.
While this other patented device operated in a generally satisfactory manner, there were still a number of disadvantages inherent in the construction. First, it has been found to be quite difficult to assemble the end flanges to the spool body, since there is a tendency for the parts to shift with respect to one another as the bolts are being installed. Second, due to the small radius of curvature of the beads on the end flanges, there is encountered difficulty in effecting a proper seating thereof. Moreover, further difficulty is experienced in determining the proper torque to be applied to the nuts, in order to achieve a balanced or uniform pressure about the spool periphery. In addition, over-tightening of one or more of the nuts results in deformation of either or both of the end flanges, causing them to weaken and assume a somewhat concave shape. Accordingly, in the above respects the disclosed patented constructions did not prove to be satisfactory from the standpoint or either strength or low manufacturing cost.
Yet another take-apart spool is disclosed in U.S. Pat. No. 1,987,990. Here again, one of the disadvantages found is that multiple parts are involved, having unusual configurations, such as internal stop shoulders and the like, requiring special metal stampings which are costly to produce.